665516720 has 80 divisors (see below), whose sum is σ = 1699096608. Its totient is φ = 240414720.

The previous prime is 665516693. The next prime is 665516723. The reversal of 665516720 is 27615566.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (665516723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135752 + ... + 140568.

Almost surely, 2^665516720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665516720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (849548304).

665516720 is an abundant number, since it is smaller than the sum of its proper divisors (1033579888).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665516720 is a wasteful number, since it uses less digits than its factorization.

665516720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4998 (or 4992 counting only the distinct ones).

The product of its (nonzero) digits is 75600, while the sum is 38.

The square root of 665516720 is about 25797.6107420823. The cubic root of 665516720 is about 873.0778901867.

The spelling of 665516720 in words is "six hundred sixty-five million, five hundred sixteen thousand, seven hundred twenty".